'anti-torpedo' originates from Modern English as a compound of the prefix 'anti-' (from Greek 'anti', meaning 'against') and 'torpedo' (ultimately from Latin 'torpere').

'torpedo' comes from Latin 'torpere' meaning 'to be numb or stiff', later used for the electric ray (Italian/Latin loanwords) and then applied in the 19th century to an explosive naval weapon; the English prefix 'anti-' was later attached to form 'anti-torpedo' to denote measures against such weapons.

Initially 'torpedo' referred to numbness and then to an electric ray; over time it came to mean a naval explosive device, and 'anti-torpedo' evolved to mean 'against or protective of torpedoes' or 'measures/devices that counter torpedoes.'